package com.yang.news.util;

import org.springframework.util.StringUtils;

import javax.servlet.http.HttpServletRequest;

/**
 * @author Billyang
 * @date 2024/11/29 11:36
 */
public class IPUtil {

    private final static String IP_FLAG_00001 = "X-Forwarded-For";
    private final static String IP_FLAG_00002 = "x-forwarded-for";

    private final static String IP_FLAG_00101 = "Proxy-Client-IP";
    private final static String IP_FLAG_00102 = "proxy-client-ip";

    private final static String IP_FLAG_00201 = "WL-Proxy-Client-I";
    private final static String IP_FLAG_00202 = "wl-proxy-client-i";

    private final static String IP_FLAG_00301 = "X-Real-IP";
    private final static String IP_FLAG_00302 = "x-real-ip";

    private final static String IP_FLAG_00401 = "REMOTE-HOST";
    private final static String IP_FLAG_00402 = "remote-host";

    private static final String UNKNOWN = "unknown";

    /**
     * 获取 IP地址
     * 使用 Nginx等反向代理软件， 则不能通过 request.getRemoteAddr()获取 IP地址
     * 如果使用了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP地址，
     * X-Forwarded-For中第一个非 unknown的有效IP字符串，则为真实IP地址
     *
     */
    public static String getRemoteIP(HttpServletRequest request) {
        String ip = request.getHeader("x-forwarded-for");
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        return "0:0:0:0:0:0:0:1".equals(ip) ? "127.0.0.1" : ip;
    }

}
